Sen. Warner wants to know what oversight, if any, would be appropriate for studies conducted by social media platforms.

A U.S. senator has asked the Federal Trade Commission to scrutinize the use of big data by Facebook and other Internet companies, following a controversy over a Facebook experiment on some of its users.

"....I think the industry could benefit from a conversation about what are the appropriate rules of the road going forward," Senator Mark R. Warner of Virginia said in a statement.

His comments Wednesday follow widespread outrage over a 2012 experiment by Facebook which adjusted the content of news feeds of 689,003 English-speaking users to study the impact on their moods.

In a letter to the FTC, Warner has asked whether the Facebook experiment violates the agency's consent agreement of 2011 with the company and also section 5 of the FTC Act which prohibits ''unfair or deceptive acts or practices."

Privacy group Electronic Privacy Information Center filed a complaint earlier this month to the FTC stating that the study, published in the Proceedings of the National Academy of Sciences, violated the privacy consent order that requires the social-networking company to protect its users' privacy, and is also a deceptive trade practice.

Warner is also aiming at the establishment of a broader framework for the use of big data that is collected by social networks. The increasing collection and analysis of big data, and its growing role in the business plans of Internet companies, raises questions whether oversight, if any, is appropriate and whether best practices should be developed and implemented by the industry or the FTC, he wrote in his letter to the FTC.

While Facebook may not have been legally required to conduct an independent ethical review of its research, the experiment raises questions whether procedures need to be in place to govern such research, Warner wrote.

The senator asked whether the FTC makes any distinction between the passive observation of user data in contrast to "actively manipulating" it. He also wants to know if consumers should be provided with more of an explicit option to opt in or out of such studies. Citing reports, he said that it was not clear whether Facebook users were adequately informed and given an opportunity to participate or not. Warner also asked the FTC if it is appropriate for research findings to be shared with participants before being made public.

However, the senator is not in favor of increased federal regulation, recommending instead industry self-regulation to address public concerns.

"It's clear that people were upset by this study and we take responsibility for it. We want to do better in the future and are improving our process based on this feedback," a Facebook spokesman said via email. "The study was done with appropriate protections for people's information and we are happy to answer any questions regulators may have."

The FTC confirmed receipt of Warner's letter but declined further comment.

The Facebook researcher behind the experiment has defended it, and said the research aimed to investigate a common concern that seeing friends post positive content leads others to feel negative or left out.( The three researchers were also concerned that exposure to friends' negativity might lead people to avoid visiting Facebook.

The Facebook algorithm reduced exposure to friends' positive emotional content in the news feed in one experiment, while reducing exposure to negative emotional content in the feed in a parallel experiment. In the paper, the authors held that the experiment procedure "was consistent with Facebook's Data Use Policy, to which all users agree prior to creating an account on Facebook, constituting informed consent for this research."

John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John's e-mail address is john_ribeiro@idg.com